System and method for setting up a call to a roaming party through an over-the-top (OTT) call service

ABSTRACT

A system and method that enables the setting up of an incoming call from an originating endpoint of a calling party to a mobile station of a called party who is registered as a roamer in a visited cellular network. In response to receiving a dialed number, or other call information, the system determines whether to set up the call to the mobile station of the called party through a pre determined, over-the-top (OTT) call service that bypasses the visited network. The OTT call service is offerable as a feature to the called party by the party&#39;s home mobile network operator (MNO). Call handling for the OTT call service is provided through i) an OTT feature server that is coordinating the incoming call, an application server that is affiliated with the OTT feature server, and iii) a OTT software application that is executing on the called party&#39;s mobile station.

CROSS REFERENCE TO RELATED APPLICATIONS

The following document is incorporated by reference herein: U.S.Provisional Application Ser. No. 62/171,084, filed Jun. 4, 2015. Ifthere are any contradictions or inconsistencies in language between thisapplication and the document that has been incorporated by referencethat might affect the interpretation of the claims in this application,the claims in this application should be interpreted to be consistentwith the language in this application.

FIELD OF THE INVENTION

The present invention relates to telecommunications in general, and,more particularly, to setting up a call from an originating endpoint ofa calling party to a mobile station of a called, roaming party throughan over-the-top (OTT) call service.

BACKGROUND OF THE INVENTION

FIG. 1 depicts a diagram of the salient components of wirelesstelecommunications system 100 in the prior art. Wirelesstelecommunications system 100 comprises the depicted data-processingsystems, which are interrelated as shown. The equipment that constitutessystem 100 includes service-control equipment, switching equipment, andradio access equipment, and is described in detail below. Wirelesstelecommunications system 100 provides wireless telecommunicationsservice to mobile station (MS) 131 when present in any of location areas140-i, for i=1 through I, wherein I is a positive integer and whosevalue equals two as depicted. System 100 provides service in accordancewith the Global System for Mobile Communications (GSM) set of standards,in which the concept of location areas is defined.

Some of the equipment components that are present in system 100 are notassociated with a specific location area 140-i. Such equipment includecomponents include i) gateway mobile switching center (GMSC) 111 and ii)home location register (HLR) 112, both of which are associated withmobile network operator (MNO) network 110 as depicted, and iii)public-switched telephone network (PSTN) 120 that providestelecommunications service to telephone 121. Mobile station 131 is notfixed to a particular location area, but can move into and be associatedwith any location area 140-i, depending on its present location. Asdepicted in FIG. 1, mobile station 131 is presently associated withlocation area 140-1.

Gateway mobile switching center (GMSC) 111 serves as a gateway betweentwo types of networks, in this case PSTN 120 and the MNO portion ofsystem 100 that serves the depicted location areas.

Home location register (HLR) 112 comprises equipment for storing acentral database that contains details of each mobile station subscriberwho is authorized to use one or more location areas as the subscriber'shome network. HLR 112 stores details of every subscriber identity module(SIM) card issued by an MNO. A SIM card comprises an integrated circuitand is used in mobile station 131. Each SIM has a unique identifiercalled an “international mobile subscriber identity,” or “IMSI.” An IMSIis a primary key to each HLR record. Another identifier that isassociated with the SIM is a “MSISDN,” which is often referred to as a“mobile station international subscriber directory number.” Each MSISDNis also a primary key to the HLR record of a subscriber. The MSISDN isthe number normally dialed by a calling party to place a call to amobile station.

The MSISDN together with the IMSI are two important numbers used foridentifying a mobile subscriber. The IMSI identifies the SIM, and theMSISDN is used for routing calls to the subscriber. The HLR data for asubscriber is stored for as long as a subscriber continues to subscribeto the service provided by the MNO network associated with HLR 112, inthis case MNO network 110.

Some subscribers who are receiving wireless services within locationarea 140-1 or 140-2 are present within their home service area.Information about these subscribers, and their SIMs and mobile stations,are stored within an HLR serving those subscribers, which HLR is notdepicted in FIG. 1 and different from HLR 112 that is servingsubscribers whose home network is network 110. Other subscribers withinlocation area 140-1 or 140-2, however, are not present within their homeservice area. Instead, they are considered “roamers” within a servicearea that is operated by an MNO that is different than their homeservice provider.

In contrast with the components described above, some of the otherequipment components that are present in system 100 are, in fact,associated with one or more specific location areas, such as locationarea 140-i. Such equipment components include visitor location register(VLR) 141-i, mobile switching center (MSC) 142-i, base stationcontroller (BSC) 143-i, and base transceiver station (BTS) 144-i.

Visitor location register (VLR) 141-i comprises equipment for storing adatabase of GSM network subscribers who have roamed into the servingarea of MSC 142-i, within a location area. In other words, VLR 141-iserves MSC 142-i. The data stored in VLR 141-i is either received fromHLR 112 or collected from mobile station 131, or both. VLRs 141-1 and141-2 communicate with HLR 112 via “D” interfaces, communicate with eachother via a “G” interface, and communicate with MSCs 142-1 and 142-2,respectively, via “B” interfaces. In some configurations, VLR 141-i isintegrated with MSC 142-i.

Mobile switching center (MSC) 142-i provides at least some of theswitching capability across location area 140-i. MSC 142-i comprises aswitch that orchestrates the provisioning and control oftelecommunications service to the mobile stations. System 100 includes aplurality of MSCs, each being responsible for a geographic region of thenetwork, in this case a particular location area. MSC 142-i is connectedto one or more BSCs (described below), and it can interface with otherMSCs.

MSC 142-i also enables a subscriber of system 100 to place a call to, orreceive a call from, another network such as Public Switched TelephoneNetwork (PSTN) 120 or other wireless networks.

Base transceiver station (BTS) 144-i is mobile station 131's accesspoint to system 100. The BTS performs speech encoding, encryption, andother functions. Communications between mobile station 131 and a BTS144-i occur over an air interface. These communications, which includecontrol signaling as well as voice, data and Short Message Service (SMS)traffic, are carried over designated channels via known methods. System100 can include a different number of BTSs than that depicted.

Base station controller (BSC) 143-i controls one or more BTSs. Forexample, the BSC handles radio channel allocation, frequencyadministration, receives power and signal measurements originating fromthe mobile stations, and controls handovers between BTSs that areconnected to the same BSC. As depicted in FIG. 1, BSC 143-i controls BTS144-i. Although BSC 143-i is depicted as being geographically remotefrom BTS 144-i, it can be co-located with a BTS or with mobile switchingcenter 142. System 100 can include multiple BSCs, even within a givenlocation area 140-i.

Regardless of whether a subscriber is in his home area or in a roamingarea, the VLR that is currently serving the subscriber and thesubscriber's own HLR continually exchange data with each other. Thisexchange of data is important, not only to provide communicationservices to the subscriber and associated mobile station, but also tokeep track of and provide only those services that are allowed for eachsubscriber and mobile station. For example, a subscriber might beallowed to use one set of services in his home area, but a different setof services while roaming in a different area. The services allowed inthe roaming area are typically a subset of the services allowed in thesubscriber's home area.

In cellular telecommunications, roaming charges are typically incurredwhenever a cellular subscriber travels outside of her mobile carrier'shome network and while in a visited network. For example, if a U.S.service provider's subscriber “A” in the United States travels to theUnited Kingdom, mobile station 131 of subscriber A is in a roaming modein which it registers with a local U.K. service provider. If someonecalls subscriber A's mobile number, the call first routes into the homenetwork of subscriber A—i.e., network 110, which is that of the U.S.provider—and then redirects to the network of the U.K. provider, inorder to reach roaming mobile station 131 in visited location area140-1. Consequently, there is a roaming charge that has to be paid tothe U.K. service provider, either by the home U.S. service provider orby the subscriber herself.

SUMMARY OF THE INVENTION

The present invention enables the setting up of an incoming call from anoriginating endpoint of a calling party to a mobile station of a calledparty who is registered as a roamer in a visited cellular network. Inresponse to receiving a dialed number, or other call information, thesystem of the illustrative embodiment determines whether to set up thecall to the mobile station of the called party through a predetermined,over-the-top (OTT) call service that bypasses the visited cellularnetwork. The OTT call service is offerable as a feature to the calledparty by the party's home mobile network operator (MNO) and can besubscribed to by the called party.

In accordance with the illustrative embodiment of the present invention,call handling for the OTT call service is provided through i) an OTTfeature server that is coordinating the incoming call, a visitorlocation register (VLR) application server that is affiliated with theOTT feature server, and iii) a OTT software application that isexecuting on the called party's mobile station. Through a priorarrangement with the home MNO, the VLR application server is permittedby the cooperative home MNO to supersede the VLR of the visited cellularnetwork, by providing the home location register (HLR) of the home MNOnetwork with information for setting up a call to the mobile station viathe OTT call service. The VLR application server of the illustrativeembodiment interacts with the HLR, which in turn interacts as neededwith the VLR of visited cellular network with which the mobile stationis registered, such that the visited cellular network remains unaware ofan incoming call being redirected for delivery through the OTT service.

Based on the aforementioned interactions and on other criteria discussedherein, the system of the illustrative embodiment determines a roamingnumber that corresponds to a point that is external to the visitedcellular network, wherein the call can be set up and routed through analternative path than that of the visited MNO network with which themobile station has registered, based on the roaming number determined.The alternative path can comprise, for example, a conditioned Internetprotocol (IP) network and a wireless access point in a computer network(e.g., WiFi, etc.). The roaming number can be determined based on thegeographic location of the mobile station.

In providing such an alternative path, the call handling technique ofthe illustrative embodiment offers a technical improvement by reducingor eliminating roaming charges that would otherwise be owed to thevisited MNO. The disclosed call handing technique can also be used tooffload a congested cellular network that would otherwise be used tohandle the incoming call to the called party registered with thatnetwork, by redirecting the call through the alternative path.Additionally, in providing an alternative path through a conditioned,optimized IP network, the quality of the call can be maintained at apredetermined level. As another advantage over some techniques in theprior art, the subscriber is not required to set up call forwarding to adifferent number than that of her mobile station when enabling callsthrough the OTT call service.

An illustrative system for setting up a call from an originatingendpoint of a calling party to a mobile station of a called partycomprising a first computer system, comprises: a receiver that isconfigured to receive, from a second computer system, a dialed numberfor the call when placed by the calling party, wherein the dialed numbercorresponds to the mobile station; a processor that is configured todetermine a roaming number based on a geographic location of the mobilestation, wherein the roaming number corresponds to a point that isexternal to a cellular network with which the mobile station isregistered; and a transmitter that is configured to transmit, to thesecond computer system, a message containing the roaming number by whichthe second computer system routes the call.

An illustrative method for setting up a call from an originatingendpoint of a calling party to a mobile station of a called party,comprises: receiving, by a first computer system from a second computersystem, a dialed number for the call when placed by the calling party,wherein the dialed number corresponds to the mobile station;determining, by the first computer system, a roaming number based on ageographic location of the mobile station, wherein the roaming numbercorresponds to a point that is external to a cellular network with whichthe mobile station is registered; and transmitting, by the firstcomputer system to the second computer system, a message containing theroaming number by which the second computer system routes the call.

An illustrative non-transitory computer-readable medium storing acomputer program comprises computer-readable instructions that, whenloaded and executed on a computer system, cause the computer system toperform the steps of a method according to any one of the precedingclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a diagram of the salient components of wirelesstelecommunications system 100 in the prior art.

FIG. 2 depicts a diagram of the salient components of wirelesstelecommunications system 200, in accordance with the illustrativeembodiment of the present invention.

FIG. 3 depicts Internet protocol (IP) network 262 withintelecommunications system 200.

FIG. 4 depicts a block diagram of the salient components of VLRapplication server 261 within telecommunications system 200.

FIGS. 5A and 5B depicts a message flow diagram of the salient processesperformed and messages exchanged in accordance with a subscriberregistering for a predetermined, over-the-top (OTT) call service of theillustrative embodiment.

FIGS. 6A and 6B depicts a message flow diagram of the salient processesperformed and messages exchanged in accordance with a subscriber, as acalled party, receiving an incoming call at mobile station 231 via theOTT call service.

FIG. 7 depicts a message flow diagram of the salient processes performedand messages exchanged in accordance with an unregistered subscriberreceiving an incoming call via the OTT call service.

DETAILED DESCRIPTION

For the purposes of this specification, the following terms and theirinflected forms are defined as follows:

-   -   The term “based on” is defined as “being dependent on” in        contrast to “being independent of”. The value of Y is dependent        on the value of X when the value of Y is different for two or        more values of X. The value of Y is independent of the value of        X when the value of Y is the same for all values of X. Being        “based on” includes both functions and relations.    -   The term “location” is defined as a zero-dimensional point, a        finite one-dimensional path segment, a finite two-dimensional        surface area, or a finite three-dimensional volume.    -   The term “location area” is a geographic region within which        wireless telecommunication service is provided to subscribers        via a non-empty set of base stations and other associated        equipment, such as a serving mobile switching center (MSC) and a        serving visitor location register (VLR). One or more location        areas can be associated with a corresponding MSC and VLR.    -   The term “mobile station” is defined as a wireless        telecommunications terminal that is capable of transmitting        and/or receiving communications wirelessly. As is well known to        those skilled in the art, a mobile station is also commonly        referred to by a variety of alternative names such as a wireless        transmit/receive unit (WTRU), a user equipment (UE), a wireless        terminal, a fixed or mobile subscriber unit, a pager, a cellular        telephone, a smartphone, a personal digital assistant (PDA), a        computer, or any other type of device capable of operating in a        wireless environment.    -   The term “mobile network operator” (MNO) is defined as a        provider of wireless communications services that owns or        controls, or both, all of the elements necessary to sell and        deliver services to an end user including radio spectrum        allocation, wireless network infrastructure, back haul        infrastructure, billing, customer care, provisioning computer        systems and marketing and repair organizations. An MNO is also        known as a wireless service provider, wireless carrier, cellular        company, or mobile network carrier,    -   The terms used to describe elements of a wireless        telecommunications network are given their industry-established        meanings, unless otherwise indicated. These terms include:        mobile switching center, base station controller, base        transceiver station, gateway mobile switching center, home        location register, visitor location register, Abis link, A-link,        B-link, D-link, G-link, and subscriber data.

The following abbreviations are used in this specification:

-   -   GSM Global System for Mobile Communications    -   MS Mobile Station    -   BTS Base Transceiver Station    -   BSC Base Station Controller    -   MSC Mobile Switching Center    -   GMSC Gateway Mobile Switching Center    -   HLR Home Location Register    -   VLR Visitor Location Register    -   MAP Mobile Application Part    -   SIP Session Initiation Protocol    -   SS7 Signaling System No. 7    -   TDM Time-Division Multiplexing    -   MNO Mobile Network Operator    -   OTT Over-The-Top    -   PSTN Public Switched Telephone Network    -   MSISDN Mobile Station International Subscriber Directory Number    -   MSRN Mobile Subscriber Roaming Number    -   IMSI International Mobile Subscriber Identity    -   TMSI Temporary Mobile Subscriber Identity    -   SIM Subscriber Identity Module

FIG. 2 depicts a diagram of the salient components of wirelesstelecommunications system 200, in accordance with the illustrativeembodiment of the present invention. Wireless telecommunications system200 comprises the depicted data-processing systems, which areinterrelated as shown. The equipment that constitutes system 200includes service-control equipment, switching equipment, and radioaccess equipment, and is described in detail below.

The illustrative embodiment provides cellular telecommunications serviceto mobile station (MS) 231 when present in any of location areas 240-i,for i=1 through I, wherein I is a positive integer and whose valueequals one as depicted. Furthermore, the illustrative embodimentprovides wireless telecommunications service to mobile station (MS) 231,in accordance with a predetermined over-the-top (OTT) call service, whenMS 231 is present in any of hotspots 270-j, for j=1 through J, wherein Jis a positive integer and whose value equals one as depicted.

System 200 enables the call termination of calls (e.g., voice calls,video calls, data calls, etc.), which can include “sessions,” to mobilestation 231 that are originated from PSTN 220, including callsoriginated from telephone 221, or from a different telecommunicationsnetwork. “Call termination” refers to the routing of telephone callsfrom one telephone company, also known as a carrier or provider, toanother. The terminating point is the “called party” or “end point.” The“originating endpoint” is that the calling party who initiates the call,such as telephone 221. The “terminating endpoint” is that of the calledparty who receives the call, such as mobile station 231. “Terminating” acall is different than “ending” or “releasing” a call.

Wireless telecommunications system 200 comprises equipment within afirst and a second mobile network operator (MNO) network—namely, MNOnetworks 210 and 250. The geographic regions covered by each MNO'snetwork can be geographically distinct. For pedagogical purposes, thefirst service provider's network is situated in New York City, while thesecond service provider's network is situated in London. As those whoare skilled in the art will appreciate after reading this specification,however, the two cellular networks can be situated in other places. Insome embodiments of the present invention, MNO networks 210 and 250, aswell as the respective equipment components therein, are controlled bydifferent business entities, while in some other embodiments the twonetworks are controlled by the same business entity. Meanwhile, PSTN 220can be associated with a separate telecommunications provider entirely.

MNO networks 210 and 250 are described in this specification as beingcellular networks providing cellular service. Although discussed withinthe context of a cellular network, in some embodiments MNO network 210and/or 250 can be another type of network in which the MNO owns and/orcontrols access to a radio spectrum license from a regulatory orgovernment entity that is different from cellular spectrum.

Some of the equipment components that are present in system 200 are notassociated with a specific location area 240-i, but nevertheless supportthe concept of location areas. Such equipment include components includei) gateway mobile switching center (GMSC) 211 and ii) home locationregister (HLR) 212, both of which provide telecommunications service formobile network operator (MNO) network 210, and iii) public-switchedtelephone network (PSTN) 220 that provides telecommunications service totelephone 221. GMSC 211, HLR 212, and PSTN 220, and telephone 221 areanalogous to GMSC 111, HLR 112, and PSTN 120, and telephone 121,respectively.

In contrast with the components described above, some of the otherequipment components that are present in system 200 are, in fact,associated with one or more specific location areas, such as locationarea 240-i. Such equipment components include visitor location register(VLR) 241-i, mobile switching center (MSC) 242-i, base stationcontroller (BSC) 243-i, and base transceiver station (BTS) 244-i.Respectively, these equipment components are analogous to VLR 141-i, MSC142-i, BSC 143-i, and BTS 144-i.

In accordance with the illustrative embodiment, cellulartelecommunications service is provided to mobile station 231, whenpresent in location area 240-i, according to the Global System forMobile Communications (GSM) set of standards. After reading thisdisclosure, however, it will be clear to those skilled in the art how tomake and use alternative embodiments of the present invention thatoperate in accordance with one or more other cellular air-interfacestandards (e.g., Universal Mobile Telecommunications System “UMTS”, LongTerm Evolution “LTE”, CDMA-2000, IS-136 TDMA, IS-95 CDMA, 3G WidebandCDMA, etc.).

The elements of a GSM network have been previously described in thisspecification and are well known to those skilled in the art. To theextent that such elements are described further in this specification,it is primarily for the purposes of establishing or describing theirrelationship with respect to elements that are germane to embodiments ofthe present invention.

Mobile station 231 comprises the hardware and software necessary tocommunicate wirelessly with network infrastructure, including asubscriber identity module (SIM) configured to store the subscriber'stelephone number (e.g., MSISDN, etc.) and IMSI. MS 231 further comprisesthe hardware and software necessary to perform the related processesdescribed below and in the accompanying figures. For example and withoutlimitation, mobile station 231 is capable of:

-   -   i. receiving an incoming (i.e., “mobile-terminated”) voice call        or other communication (e.g., SMS text, data, etc.),    -   ii. transmitting an outgoing (i.e., “mobile-originated”) voice        call or other communication (e.g., SMS text, data, etc.), and    -   iii. receiving, transmitting, or otherwise processing one or        more signals in support of capabilities i and ii.

Mobile station 231 comprises the hardware and software necessary to beGSM-compliant and to perform the related processes described below andin the accompanying figures. After reading this disclosure, however, itwill be clear to those skilled in the art how to make and usealternative embodiments of the present invention in which MS 231operates in accordance with one or more other cellular air-interfacestandards, as already enumerated.

Mobile station 231 further comprises the hardware and software necessaryto be WiFi-compliant and to perform the related processes describedbelow and in the accompanying figures. After reading this disclosure, itwill be clear to those skilled in the art how to make and usealternative embodiments of the present invention that operate inaccordance with one or more other computer network standards (e.g., IEEE802.16 WiMax, Bluetooth, LoRa, etc.) in one or more frequency bands,including, but not limited to, personal area network (PAN) standards andlocal area network (LAN) standards.

Mobile station 231 can move into and be associated with any locationarea 240-i, depending on its present location. MS 231 can also move intoand be associated with any WiFi hotspot 270-j, depending on its presentlocation. As depicted in FIG. 2, mobile station 231 is presentlyassociated with WiFi hotspot 270-1, even though it is also within thecoverage area that corresponds to area 240-1.

Mobile station 231 is capable of executing an over-the-top (OTT)application, or “app”, pre-programmed with awareness of the mobilenetwork operator of network 210. The OTT app enables the mobile station,and thus its user, to access the corresponding OTT call service as acalled party in a given call or as a calling party, for that matter.

By processing a call via the OTT app of the illustrative embodiment, MS231 uses a computer network (e.g., LAN, PAN, etc.) to access theInternet, such as the computer network accessible via hotspot 270-1, inorder to access the corresponding OTT call service to complete the call.This is, in contrast, to the mobile station relying directly on acellular network itself, such as cellular network 250 accessible inlocation area 240-1, to handle at least some of the call control andswitching of the call. In fact, MS 231 is capable of communication via aradio channel within a cellular network concurrently with the mobilestation being attached to a wireless computer network.

Although wireless telecommunications system 231 as depicted comprisesonly one mobile station, it will be clear to those skilled in the art,after reading this disclosure, how to make and use alternativeembodiments of the present invention that comprise any number of mobilestations.

In addition to the equipment components described thus far, some of theother equipment components that are present in system 200 are agnosticto any GSM location area. Such equipment components include VLRapplication server 261, Internet protocol network 262, router 271-j, andaccess point 272-j, wherein j has a value equal to one as depicted.

VLR application server 261, a computer system, comprises equipment forstoring a database of OTT call service subscribers who have roamed intothe serving area defined by hotspot 270-j. The data stored in server 261is either received from HLR 212 or collected from mobile station 231, orboth. Server 261 communicates with HLR 212 via a “D” interface, orequivalent, and also communicates with Internet protocol network 262.Server 261, which is further described in FIG. 4, further comprises thehardware and software necessary to perform the related processesdescribed below and in the accompanying figures.

Internet protocol (IP) network 262 is a serves as an alternative routingpath (e.g., alternative to cellular network 250, etc.) for at least someof the call services provided within telecommunications system 200, inaccordance with the illustrative embodiment of the present invention,described below and in FIG. 3.

Feature server 263, a computer system, comprises equipment forcoordinating the OTT call service of the illustrative embodiment. Server263 further comprises the hardware and software necessary to perform therelated processes described below and in the accompanying figures.

In regard to feature server 263, this computer system comprises at leastone server computer that performs at least some of the tasks disclosedherein. In some embodiments of the present invention, server 263comprises at least some of the components as those of VLR applicationserver 261, which are described below and in FIG. 4. As those who areskilled in the art will appreciate after reading this specification, thehardware platform performing at least some of the tasks performed byfeature 263 can be embodied as a multi-processor platform, as asub-component of a larger computing platform, as a virtual computingelement, or in some other computing environment—all within the scope ofthe present invention.

As those who are skilled in the art will appreciate after reading thisspecification, feature server 263 can be a different type of apparatusthan a server computer, and can be referred to by a different name suchas a data-processing system, a computer system, a computing device, oranother type of hardware platform that comprises one or more processors,one or more memories, and one or more network interfaces, for exampleand without limitation.

As depicted in FIG. 2, feature server 263, VLR server 261, and IPnetwork 262 constitute communication service provider (CSP) network 260.Communication service provider (CSP) network 260 is a network thattransports information electronically. In accordance with theillustrative embodiment of the present invention, CSP network 260 isthat of a telecommunications service provider (TSP). Elements 261through 263 are depicted as all being within network 260; however, asthose who are skilled in the art will appreciate after reading thisspecification, one or more of elements 261 through 263 can be situatedoutside of network 260. In some embodiments of the present invention,one or both of elements 261 and 263 are implemented in a cloud-basedservice.

In some embodiments of the present invention, networks 210 and 260including their respective equipment components are controlled bydifferent business entities, while in some other embodiments the twonetworks are controlled by the same business entity. In some embodimentsof the present invention, networks 250 and 260 including theirrespective equipment components are controlled by different businessentities, while in some other embodiments the two networks arecontrolled by the same business entity.

FIG. 3 depicts Internet protocol (IP) network 262 withintelecommunications system 200. IP network 262 serves as an alternativerouting path for at least some of the call services provided withintelecommunications system 200, in accordance with the illustrativeembodiment of the present invention. IP network 262 comprisescomputer-networking devices, namely media gateways 301 through 304 androuters 311 through 315. Although four gateways and five routers aredepicted, network 262 can comprise any number of gateways, routers, andnetworking devices in general.

In accordance with the illustrative embodiment, network 262 is a tier 1IP network. In some alternative embodiments of the present invention,however, network 262 can be a different type of service providernetwork, such as a tier 2 IP network, for example and withoutlimitation. Furthermore, in some embodiments of the present invention,IP network 262 can also serve as a backbone Internet service providernetwork as is known in the art and, as such, can be referred to as a“backbone service provider network.”

IP network 262 is capable of coordinating quality-of-service- (QoS-)enabled IP service for traffic prioritization between GMSC 211 andwireless access point 272-j, in some embodiments of the presentinvention. As video and voice are latency-sensitive applications, it canbe inefficient to give file sharing and email applications the samepriority in the delivery. IP network 220 can enable at least a portionof telecommunications system 200 to provide to video, voice, and otherlatency-sensitive applications higher QoS to improve the networkutility.

Wireless access point 272-j communicates with mobile station 231 viaWiFi-enabled radio, by providing hotspot 270-j, and also communicateswith IP Network 262 via router 271-j. In accordance with theillustrative embodiment, each wireless access point 272-j has one ormore antennas that are associated with the access point, in order toenable communication with mobile station 231. The coverage of hotspot270-j provided by a wireless access point might or might not overlapwith the coverage of location area 240-i.

Although the illustrative embodiment comprises one wireless accesspoint, it will be clear to those skilled in the art, after reading thisdisclosure, how to make and use alternative embodiments of the presentinvention that comprise any number of wireless access points.

FIG. 4 depicts a block diagram of the salient components of VLRapplication server 261, in accordance with the illustrative embodimentof the present invention. Server 261, a server computer, comprises:processor 401, memory 402, and network interface module 403, which areinterconnected as shown.

Server 261 comprises at least one server computer that performs at leastsome of the tasks disclosed herein. As those who are skilled in the artwill appreciate after reading this specification, the hardware platformperforming at least some of the tasks performed by server 261 can beembodied as a multi-processor platform, as a sub-component of a largercomputing platform, as a virtual computing element, or in some othercomputing environment—all within the scope of the present invention.

As those who are skilled in the art will appreciate after reading thisspecification, server 261 can be a different type of apparatus than aserver computer, and can be referred to by a different name such as adata-processing system, a computer system, a computing device, oranother type of hardware platform that comprises one or more processors,one or more memories, and one or more network interfaces, for exampleand without limitation.

Processor 401 is a general-purpose processor that is configured toexecute operating system 411 and application software 412, and topopulate, amend, use, and manage database 413, as described in detailbelow and in the accompanying figures. For the purposes of thisspecification, a “processor” is defined as one or more computationalelements, whether co-located or not and whether networked together ornot.

Memory 402 is non-transitory and non-volatile computer storage memorytechnology that is well known in the art (e.g., flash memory, etc.).Memory 402 is configured to store operating system 411, applicationsoftware 412, and database 413. The operating system is a collection ofsoftware that manages server 261's hardware resources and providescommon services for computer programs, such as those that constitute theapplication software. The application software that is executed byprocessor 401 enables server 261 to perform at least some of thefunctions disclosed herein. Database 413 comprises information fordifferent subscribers (e.g., IMSI, MSRN, OTT call serviceidentification, etc.) of the OTT service or services of the illustrativeembodiment, their availabilities at any given moment through the OTTservice or services (e.g., “available”, “not available”, etc.), andinformation about their mobile stations (e.g., MSISDN, etc.).

Memory 402 is a non-transitory computer-readable medium storing acomputer program comprising computer-readable instructions that, whenloaded and executed on server 261, cause server 261 to perform at leastsome of the tasks described herein.

It will be clear to those having ordinary skill in the art how to makeand use alternative embodiments that comprise more than one memory 402;or comprise subdivided segments of memory 402; or comprise a pluralityof memory technologies that collectively store the operating system,application software, and database.

Network interface module 403 comprises a network adapter configured toenable server 261 to transmit information to and receive informationfrom other parts of telecommunications system 200. Module 403 comprisesreceiver 403-1 configured to receive and transmitter 403-2 configured totransmit.

FIGS. 5 through 7 depict message flow diagrams that are representativeof various operating scenarios of telecommunications system 200. Theprocesses performed by wireless telecommunications system 200 of theillustrative embodiment are depicted in the drawings (i.e., FIG. 5 andsubsequent figures) as being performed in a particular order. It will,however, be clear to those skilled in the art, after reading thisdisclosure, that these operations can be performed in a different orderthan depicted or can be performed in a non-sequential order (e.g., inparallel, etc.). In some embodiments of the present invention, some orall of the depicted processes might be combined or performed bydifferent devices. In some embodiments of the present invention, some ofthe depicted processes might be omitted.

Subscriber Registration—FIGS. 5A and 5B depicts a message flow diagramof the salient processes performed and messages exchanged in accordancewith a subscriber registering for a predetermined, over-the-top (OTT)call service of the illustrative embodiment. As an overview, when asubscriber registers, feature server 263 initiates the subscriber'sregistration with VLR server 261. In turn, VLR server 261 informs HLR212 that the subscriber is presently roaming and is registered at VLRserver 261.

A brief discussion of the types of messages exchanged between HLR 212and VLR server 261 is provided here. In accordance with the illustrativeembodiment, VLR server 261 utilizes standardized messages in order toensure compatibility with HLR 212. Compatibility with at least HLR 212is necessary because it is assumed that no hardware or softwaremodifications are possible at HLR 212. The standardized messages used inthe illustrative embodiment are described in detail in “Digital cellulartelecommunications system (Phase 2+); Mobile Application Part (MAP)specification (GSM 09.02), Version 5.3.0,” which is incorporated hereinby reference.

As one example of a standardized message utilized, VLR server 261 isconfigured to transmit a MAP/D UPDATE LOCATION message to HLR 212,having the effect of HLR 212 updating its record to point to server 261as the new VLR until otherwise notified.

Standardized messages are used in accordance with the illustrativeembodiment. However, it will be clear to those skilled in the art, afterreading this specification how to make and use alternative embodimentsin which one or more alternative messages, standardized or otherwise,are used instead of the standardized messages described below.

Referring to FIG. 5A, at process 501, MS 231 detects a power-oncondition, as a result of the subscriber powering-on the mobile station.As a result, MS 231 transmits message 503 to initiate the registrationprocess with the GSM cellular network. The sequence for registering witha GSM network is well known in the art and will not be discussed here.

At process 505, VLR 241-1 transmits message 507 to indicate that theregistration process with the GSM network has been completed. At thispoint, MS 231 is registered with cellular network 250 and is capable offurther communication (e.g., receiving and/or transmitting messages,etc.) with network 250 via one or more radio channels within network250.

At process 509, MS 231 acquires the WiFi network provided by hotspot270-1. As a result, MS 231 transmits message 511 to feature server 263,in order to register with the OTT call service. In accordance with theillustrative embodiment, the corresponding software applicationexecuting on MS 231 initiates the transmitting of message 511 to server263. In some embodiments of the present invention, MS 231 waits untilafter receiving message 507 (i.e., until after GSM network registrationis completed), while in other embodiments MS 231 transmits message 511before receiving message 507 (i.e., before GSM network registration iscompleted).

In accordance with the illustrative embodiment, MS 231 has been provided(e.g., via downloading, etc.) with a software application (i.e., “app”)that corresponds to the predetermined OTT call service. It is the appexecuting at MS 231 that executes process 509, which providesregistration of MS 231 with network 260 that is external to and/orindependent of cellular network 250.

At process 513, feature server 263 transits message 515 to VLRapplication server 261 in response to receiving message 511. Inaccordance with the illustrative embodiment, message 515 is in the formof an HTTPS (SUB_REG) request containing the subscriber's telephonenumber, the dialed number (i.e., the MSISDN). In some embodiments,exchanges between servers 261 and 263 can be implemented in accordancewith the Session Initiation Protocol (SIP).

At process 517, VLR server 261 transmits message 519 to HLR 212 inresponse to receiving message 515 and after checking that the subscriberis not already registered with server 261. In accordance with theillustrative embodiment, message 519 is in the form of a SEND IMSIREQUEST message containing the telephone number (i.e., the MSISDN) ofthe subscriber.

At process 521, HLR 212 transmits message 523 to VLR server 261 inresponse to receiving message 519. Message 523 contains the IMSI of thesubscriber.

At process 525, VLR server 261 transmits message 527 to HLR 212 inresponse to receiving the IMSI of the subscriber. In accordance with theillustrative embodiment, message 527 is in the form of a MAP/ANY TIMEINTERROGATION (ATI) REQUEST message. In some alternative embodiments,this and/or possibly other messages described below can be exchangedbetween VLR application server 261 and VLR 241-1 directly, instead ofinvolving HLR 212.

At process 529, HLR 212 transmits message 531 to VLR 241-1—that is, theVLR in the GSM network at which the subscriber is currentlyregistered—in response to receiving message 527. In accordance with theillustrative embodiment, message 531 is in the form of a MAP/PROVIDESUBSCRIBER INFO REQUEST message.

At process 533, VLR 241-1 transmits message 535 to HLR 212 in responseto receiving message 531. In accordance with the illustrativeembodiment, message 535 is in the form of a MAP/PROVIDE SUBSCRIBER INFORESPONSE message.

Continuing in FIG. 5B, HLR 212 at process 537 transmits message 539 toVLR server 261 in response to receiving message 535, thereby returningthe current GSM network VLR information. In accordance with theillustrative embodiment, message 539 is in the form of a MAP/ANY TIMEINTERROGATION (ATI) RESPONSE message.

VLR server 261 stores the current GSM network VLR information for lateruse. For example, if and when MS 231 later on is no longer being servedby hotspot 270-1 (e.g., moves out of the hotspot, etc.), VLR server 261can send a MAP/PRN message to VLR 241-1 using the subscriber's lastknown VLR information obtained by the ATI message sequence.Advantageously, this avoids MS 231 being in limbo with regard to HLR 212and future incoming calls.

At process 541, VLR server 261 transmits message 543 to HLR 212 inresponse to receiving message 539, thereby providing the OTT callservice's VLR information. In accordance with the illustrativeembodiment, message 543 is in the form of a MAP/UPDATE LOCATION message.

In some embodiments of the present invention, a GSM UPDATE PARAMETERSsequence, or equivalent, can also be performed here involving VLR 241-1.

At process 545, HLR 212 transmits acknowledgment message 547 to VLRserver 261 in response to receiving message 543.

At process 549, VLR server 261 transmits message 551 to feature server263 in response to a successful registration of the subscriber.

At process 553, feature server 261 transmits message 555 to MS 231 inresponse to a successful registration of the subscriber.

Incoming Call to Subscriber—FIGS. 6A and 6B depicts a message flowdiagram of the salient processes performed and messages exchanged inaccordance with a subscriber, as a called party, receiving an incomingcall at mobile station 231 via the OTT call service. As an overview,while the subscriber is registered with VLR server 261 and the featureserver 263, all incoming call requests to the subscriber's telephonenumber (i.e., the MSISDN) is forwarded to the servers 261 and 263 forprocessing. Furthermore, given that the subscriber is in a visitinglocation, an appropriate local number is provided to HLR 212 to forwardthe call to. Advantageously, this can result in a least-cost route forthe call. It is important to note that while these actions are takingplace within networks 210 and 260, MS 231 can also be capable (i.e., canconcurrently maintain its capability) of communication via a radiochannel within cellular network 250.

For pedagogical purposes, VLR server 261 is sometimes referred to inthis specification as a “first computer system”, HLR 212 is sometimesreferred to as a “second computer system”, and feature server 263 issometimes referred to as a “third computer system”.

Referring to FIG. 6A, at process 601, GMSC 211 detects an incoming callbeing received from telephone 221, an originating endpoint of a callingparty. As a result, GSMC 211 transmits message 603 to HLR 212,indicating the incoming call information.

At process 605, HLR 212 transmits message 607 to VLR server 261 inresponse to receiving message 603. In accordance with the illustrativeembodiment, message 607 is in the form of a MAP/PROVIDE ROAMING NUMBERREQUEST message. Server 261 receives the message at process 608.

At process 609, VLR server 261 transmits message 611 to feature server263 in response to receiving message 607, in order to determine whetherthe subscriber is still registered with server 263. More generally,server 261 is determining what the availability of the called party isthrough the over-the-top (OTT) call service of the illustrativeembodiment, wherein feature server 263 coordinates the OTT call service.

At process 613, if the subscriber is still registered, feature server263 transmits message 615 to VLR server 261. (FIG. 7 depicts a messageflow for the scenario in which the subscriber is not registered.)

At process 616, VLR server 261 determines a roaming number based on ageographic location of MS 231 and/or other business logic, in theprocess retrieving an MSRN appropriate for routing towards MS 231, inresponse to receiving message 615. In at least some embodiments of thepresent invention, the roaming number corresponds to a point (e.g.,spot, place, position, etc.) that is external to cellular network 250,and in determining the roaming number server 261 does not use cellularnetwork 250 as a frame of reference. In some embodiments of the presentinvention, a roaming number that corresponds to a point that is externalto network 250 can be one that is selected from an address space that isoutside of the address space of network 250, wherein the point itselfcan be based on the geographic location of MS 231. The geographiclocation of MS 231 used in determining the roaming number is independentof cellular network 250.

In accordance with the illustrative embodiment, server 261 uses anIP-based geolocation, which is an IP address location, in order todetermine the closest equipment component (e.g., a gateway, etc.) to MS231, within network 260 and retrieves the roaming number (i.e., theMSRN) corresponding to that equipment component. In some embodiments,this can be obtained via GeoIP™, or other suitable system. In someembodiments of the present invention, the geolocation of MS 231 is basedon an IP address assigned to the mobile station by the OTT call servicebeing coordinated by feature server 263.

At process 617, server 261 then transmits to HLR 212 message 619containing the retrieved MSRN as the roaming number. In accordance withthe illustrative embodiment, message 619 is in the form of a MAP/PROVIDEROAMING NUMBER RESPONSE message.

At process 621, HLR 212 transmits message 623 to GMSC 211, therebyforwarding the MSRN.

At process 625, GMSC 211 transmits message 627 to media gateway 301within IP network 262, thereby forwarding information for the incomingcall. In some embodiments, GMSC 211 uses the received MSRN to determinewhether to route the call to IP network 262 (e.g., via dedicated linessuch as SIP or TDM trunks), in contrast to another network such ascellular network 250. For example and without limitation, GMSC 211 mighthave pre-stored one or more MSRNs that correspond to locations within IPnetwork 262; upon receiving an MSRN with a value matching that of apre-stored MSRN, GMSC 211 routes the call to IP network 262, which thenfurther resolves how to use MSRN, as described below.

At process 629, upon receiving the incoming call, media gateway 301,which is at the ingress point from GMSC 211 and within IP network 262,queries routing logic (e.g., via an intermediary computer system, etc.)via message 631 to determine the route the call will take to an egresspoint.

At process 633, feature server 263 determines the egress point within IPnetwork 262. Server 263 does so by determining the geolocation of MS 231corresponding to the roaming number (i.e., the MSRN). As explainedearlier, this can be accomplished by retrieving the IP geolocationinformation to identify the region of the world that MS 231 with respectto IP network 262. In accordance with the illustrative embodiment,server 263 selects the computer-networking device within IP network 262based on proximity to MS 231 (e.g., the gateway closest geographicallyto MS 231), in this case device 303. As those who are skilled in the artwill appreciate after reading this specification, however, a differentcriterion can be used to select the media gateway, either based on theMSRN or independent of the MSRN.

Feature server 263 then transmits message 635, thus providing theidentity of the egress point to device 301.

At process 637, media gateway 301 routes that call by forwarding theincoming call information via message 639 and across possibleintermediate switching devices, to the media gateway corresponding tothe MSRN, namely media gateway 303 within IP network 262. A serviceprovider different than that of cellular network 250 controls thecomputer-networking devices within IP network 262 and through which thecall is routed.

At process 641, media gateway 303 forwards the incoming call informationto feature server 263 via message 643, in order to notify MS 231 of theincoming call. For example and without limitation, this can beaccomplished via Session Initiation Protocol (SIP) as can be at leastsome of the other call signaling tasks. Server 263 receives theinformation at process 644. In some embodiments, a Session BorderControl (SBC) is used in addition to or in place of feature server 263,in order to exchange messages between IP network 262 and MS 231.

At process 645, server 263 forwards the incoming call information to MS231 via message 647, which rings the subscriber at process 649.

Once the subscriber answers at MS 231 and the setup of the call iscompleted, the data packets of the call are transferred between GMSC 211at the telephone 221 side of the call and MS 231, as depicted by datastream 651.

Incoming Call to Subscriber Not Registered—FIG. 7 depicts a message flowdiagram of the salient processes performed and messages exchanged inaccordance with an unregistered subscriber receiving an incoming callvia the OTT call service.

At process 701, and similar to process 601 in FIG. 6A, GMSC 211 detectsan incoming call being received from telephone 221. As a result, GSMC211 transmits message 703 to HLR 212, indicating the incoming callinformation.

At process 705, HLR 212 transmits message 707 to VLR server 261 inresponse to receiving message 703. In accordance with the illustrativeembodiment, message 707 is in the form of a MAP/PROVIDE ROAMING NUMBERREQUEST message.

At process 709, VLR server 261 transmits message 711 to feature server263 in response to receiving message 707, in order to determine whetherthe subscriber is still registered with server 263.

At process 713, if the subscriber is not still registered, featureserver 263 transmits message 715 to VLR server 261.

At process 717, VLR server 261 transmits message 719 to HLR 212, with an“absent subscriber” error code.

At process 721, HLR 212 disposes of the incoming call accordingly, inresponse to receiving the error code.

It is to be understood that the disclosure teaches just one example ofthe illustrative embodiment and that many variations of the inventioncan easily be devised by those skilled in the art after reading thisdisclosure and that the scope of the present invention is to bedetermined by the following claims.

What is claimed is:
 1. A system for setting up a call from anoriginating endpoint of a calling party to a mobile station of a calledparty, the system comprising: a first computer system, the firstcomputer system comprising: a receiver that is configured to receive,from a second computer system, a request for a roaming number and adialed number for the call when placed by the calling party, wherein thedialed number corresponds to the mobile station and a cellular networkwith which the mobile station is registered as a roamer; a processorthat is configured to determine, in response to the request for theroaming number, an availability of the called party through apredetermined over-the-top (OTT) call service, and the roaming numberbased on the availability of the called party; and a transmitter that isconfigured to: transmit, to a third computer system configured tocoordinate the predetermined OTT call service, a request about theavailability of the called party through the predetermined OTT callservice; and transmit, to the second computer system, the roaming numberbased on the determined availability of the called party; wherein, inresponse to the request about the availability of the called partythrough the predetermined OTT call service, the third computer systemtransmits a message to the first computer system, which indicates thatthe called party is available through the predetermined OTT callservice; and wherein the roaming number determined by the processor andtransmitted by the transmitter is based on a geographic location of themobile station, wherein the roaming number corresponds to a point thatis external to the cellular network with which the mobile station isregistered as the roamer; and wherein, based on the roaming number, thesecond computer system routes the call through a path that bypasses thecellular network with which the mobile station is registered as theroamer.
 2. The system of claim 1 further comprising a firstcomputer-networking device that is configured to route the call to asecond computer-networking device based on the roaming number, whereinboth the first and second computer-networking devices are external tothe cellular network.
 3. The system of claim 2 wherein the thirdcomputer system that is further configured to: receive a first signalbased on the call being routed to the second computer-networking device,and transmit, to the mobile station, a second signal for notifying thecalled party of the call, based on the first signal.
 4. The system ofclaim 2 wherein the second computer-networking device is selected basedon the determining of the geographic location of the mobile station, andwherein the roaming number corresponds to the second computer-networkingdevice.
 5. The system of claim 4 wherein the second computer-networkingdevice is selected based on its geographical proximity to the mobilestation.
 6. The system of claim 1 wherein the processor of the firstcomputer system is configured to determine the roaming number based ondetermining the geographic location of the mobile station based on anInternet protocol address assigned to the mobile station by thepredetermined OTT call service.
 7. The system of claim 1 wherein thesecond computer system comprises a Home Location Register (HLR)database.
 8. The system of claim 1 wherein the roaming number is amobile subscriber roaming number (MSRN).
 9. The system of claim 1wherein a first mobile network operator (MNO) that controls the secondcomputer system and a second MNO that controls the cellular network aredifferent.
 10. A method for setting up a call from an originatingendpoint of a calling party to a mobile station of a called party, themethod comprising: receiving, by a first computer system from a secondcomputer system, a request for a roaming number and a dialed number forthe call when placed by the calling party, wherein the dialed numbercorresponds to the mobile station and a cellular network with which themobile station is registered as a roamer; determining, by the firstcomputer system, in response to the request for the roaming number, anavailability of the called party through a predetermined over-the-top(OTT) call service, and the roaming number based on the availability ofthe called party; transmitting, by the first computer system to a thirdcomputer system configured to coordinate the predetermined OTT callservice, a request about the availability of the called party throughthe predetermined OTT call service; in response to the request about theavailability of the called party through the predetermined OTT callservice, transmitting, by the third computer system, a message to thefirst computer system, which indicates that the called party isavailable through the predetermined OTT call service; in response to themessage from the third computer system that indicates that the calledparty is available through the predetermined OTT call service,transmitting, by the first computer system to the second computersystem, the roaming number determined by the first computer system, theroaming number based on a geographic location of the mobile station andthe roaming number corresponding to a point that is external to thecellular network with which the mobile station is registered as theroamer; and based on the roaming number, routing, by the second computersystem, the call through a path that bypasses the cellular network withwhich the mobile station is registered as the roamer.
 11. The method ofclaim 10 further comprising routing the call, from a firstcomputer-networking device to a second computer-networking device, basedon the roaming number, wherein both the first and secondcomputer-networking devices are external to the cellular network. 12.The method of claim 11 further comprising: receiving, by the thirdcomputer system, a first signal based on the call being routed to thesecond computer-networking device; and transmitting, by the thirdcomputer system to the mobile station, a second signal for notifying thecalled party of the call, based on the first signal.
 13. The method ofclaim 11 further comprising selecting the second computer-networkingdevice based on the determining of the geolocation of the mobilestation, wherein the roaming number corresponds to the secondcomputer-networking device.
 14. The method of claim 13 wherein thesecond computer-networking device is selected based on its geographicalproximity to the mobile station.
 15. The method of claim 10 wherein thedetermining of the roaming number comprises determining the geolocationof the mobile station based on an Internet protocol (IP) addressassigned to the mobile station by the predetermined over-the-top OTTcall service.
 16. The method of claim 10 wherein the second computersystem comprises a Home Location Register (HLR) database.
 17. The methodof claim 10 wherein the roaming number is a mobile subscriber roamingnumber (MSRN).
 18. The method of claim 10 wherein a first mobile networkoperator (MNO) that controls the second computer system and a second MNOthat controls the cellular network are different.
 19. A non-transitorycomputer-readable medium storing a computer program comprisingcomputer-readable instructions that, when loaded and executed on acomputer system, cause the computer system to perform the steps of amethod according to claim 10.